The control of beef quality and more particularly of its sensory characteristics (tenderness, flavor, juiciness and color) is important for beef producers and retailers in order to satisfy consumer's requirements and wishes. Multiple factors control beef sensory quality traits and thus induce great variation in them. It has been shown that meat sensory quality depends not only on production factors such as breed, genotype, age, diet, growth path or slaughter weight (Cassar-Malek I et al., Animal Science, 2004; Cuvelier C. et al., Animal Science, 2006, Monson F et al., Meat Science, 2004; Monson F. et al. Meat Science, 2005; Sami A S et al. Meat Science, 2004; Sanudo C. et al. Meat Science, 2004.), for review, see Geay Y. et al., Reprod Nutr Dev, 2001, but also on technical factors (slaughtering conditions, ageing time, cooking process) (Monson F. et al., Meat Science, 2004; Monson F. et al., Meat Science, 2005).
Genetic and rearing factors are known to affect biological characteristics of muscles (fiber type, collagen, intramuscular adipose tissue, protease activities) which in turn regulate tenderness and flavor. Tenderness has two major components: the background toughness which results from the connective tissue characteristics (mainly collagen content and solubility) and the myofibrillar component closely related to the muscle fiber characteristics (Klont R E et al., Meat Science, 1998) which control the tenderization phase characterized by post-mortem proteolysis, a major biological process involved in the conversion of muscle into meat (Koohmaraie M. et al., Meat Science, 2002; Veiseth E. et al., Indicators of milk and beef quality, EAAP Publication 112, Wageningen Academic Publishers, Wageningen, The Netherlands, 2005). The intramuscular fat and its fatty acids composition determine meat flavor, and lipid oxidation is responsible for odors usually described as rancid (Campo M M. et al., Meat Science, 2006, Wood J D et al., Meat Science, 2003). Juiciness is more difficult to evaluate but it can be influenced by the structure of meat and its water binding capacity (for review see Hocquette J F et al., Ital J Anim Sci, 2005). However, Renand et al., Meat Science, 2001, have shown that only less than one third to a quarter only of the variability in tenderness and flavor can be explained by the variability in muscle characteristics of live animals.
Muscle biological characteristics are under the control of several genes expression. Functional genomics (which includes analysis of the transcriptome and proteome) provides news opportunities for determining the molecular processes related to meat quality (Eggen A. et al., Meat Science, 2003). Microarray technology enables multiple genes associated with variation in different sensory traits to be identified. However until now, only few studies have been conducted in this connection either in pigs (Plastow G S et al., Meat Science, 2005), or in cattle (Sudre K et al., Meat Science, 2005; Wang Y H et al., Mamm Genome, 2005.), mainly due to the lack of appropriate and specific tools in livestock species. Therefore, a great deal of effort has been devoted to the preparation of cDNA arrays specific for bovines (for instance, see Bernard C et al., J Physiol Pharmacol, 2005 and Lehnert S A et al., Australian Journal of Experimental Agriculture, 2004). In parallel, new technologies based on oligonucleotide arrays have been developed as well as an accurate selection of muscle-specific probes from studies in mammals (Lamirault G et al., J Mol Cell Cardiol, 2006).
Various methods of meat tenderness detection are known in order to assess whether a meat is tender. In particular, studies have been made of the physico-chemical properties of the muscle have been made. Indeed, the principle of comparing the biochemical characteristics and the sensory characteristics of the meat is known. Within the framework of this comparison, it has been shown that biochemical characteristics explain individually more than 25% of the variability in tenderness (Renand et al., Meat Science 2001; Brouard et al., Rencontres Recherches Ruminants 2001; review by Hocquette et al., Italian Journal of Animal Science 2005).
Other studies have demonstrated the involvement of genes in the tenderness of meat. More particularly, it has been shown that these genes have effect on the molecular composition of the muscle fibers. In particular, genomic markers associated with the tenderness of the meat are known. In the document US 2005/0181373A1, a gene encoding for a neutral protease activated by calcium or mu-calpain is described, which is used to initiate an identification process of different populations or breeds of ruminant mammals such as bovines.
In the document WO02/064820A1, a gene encoding for calpastatin (CAST) is described, which is used to identify animals which provide tender meat.